From the title alone, “Let’s Be Cops” makes it clear its ambitious are slight, with the comedy not asking much of the audience except to sit back and let the premise of two guys pretending to be police officers go wild. But any goodwill will likely depend on how much they can tolerate a production this lazy. Not resembling a movie as much as a series of loosely connected skits that eventually cohere into something resembling a motion picture, filled with a handful of odd continuity issues, dangling plot threads, and most importantly, the problem of being deeply unfunny, ‘Let’s Be Cops’ is a fine example of what happens when filmmakers rely too heavily on the potential chemistry of the cast, rather than giving actors something decent on the page to work with.

Luke Greenfield, who has quickly lost whatever credit he had for directing the better-than-it-should-have-been “The Girl Next Door” a decade ago (which he notably did not write), is the cowriter and director of this film, starring “New Girl” duo Jake Johnson and Damon Wayans Jr.. Respectively, they play Ryan and Justin (though they might as well by playing Nick and Coach), two best buds who moved from Ohio to make their dreams come true in Los Angeles (shot in Atlanta) by the time they hit thirty, only to find the future didn’t turn out as planned. Former college football hero Ryan is coasting on the paltry money he made from a television ad for herpes, while Justin has an unsatisfying job at a video game company where his pitches are ignored. The cop uniforms emerge when the pair dress up as police officers for their college reunion, thinking it’s a costume party when it’s actually a masquerade. Embarrassed by their lack of upward mobility, they leave the party with their gear still on, but suddenly notice they command a newfound respect and sexual appeal when wearing a badge and a gun. And you know what happens next….

Yep, the pair decide to keep the uniforms on and what follows is a series of semi-sketches finding Ryan and Justin getting into predictable trouble and bickering tediously. Justin is hesitant with how far Ryan is taking the ruse, with the latter buying a police car on eBay and retrofitting it with LAPD decals and a siren. Doing so is highly illegal, but the pair soon realize they are in too deep when an anonymous bunch of swarthy gangsters start shaking down the restaurant owned by immigrant parents of Justin’s love interest, waitress and (conveniently for the plot) aspiring makeup artist Josie (Nina Dobrev, who thinks her boyfriend is a real cop). And so a half baked plot comes together in the second half, involving a conspiracy the two must expose while staying out of jail themselves.

While there could be a better movie made with this concept, everything about “Let’s Be Cops” feels uncertain. Though tagged with an R-rating, it’s unclear why 20th Century Fox even bothered, as it was clearly shot with an option for PG-13 and leans heavily in that direction. Aside from one appearance of testicles and a few f-bombs, there is nothing here rising to the level of R-rated raunch. Even a potentially inspired sequence finding Justin high on crystal meth is disappointingly unrealized (though it does inspire a couple laughs as Wayans Jr. finally gets to do something other than complain). And the story wobbles from loose, goodtime comedy hijinks for the first two-thirds of the film to more dramatic fare towards the climax. Through his characters, Greenfield grasps at taking gun violence seriously, but can’t help himself with all kinds of shoot ’em up fun and slow-mo shots of Ryan and Justin getting weaponized and suited up for a final battle. And story elements are dropped in haphazardly with little reason or substance, such as Ryan’s mentorship with a neighborhood boy.

It’s a shame. Jake Johnson is a talented performer, performing this exact role so much better on “New Girl,” with the significant difference that he has an actual script and character to play. So too is Wayans Jr., who spends most of the picture screaming in fear, reluctantly joining Johnson in whatever scheme is being cooked up, but rarely being given a chance to really flex his comedic muscles. Speaking of which, it’s mind boggling that Rob Riggle shows up, playing the straightman (what a waste), while we wonder what mortgage Andy Garcia paid off by sleepwalking through this token villain role. So it’s a huge relief when Keegan-Michael Key shows up. He plays Pupa, the tattooed, patois slinging enemy turned pal to Justin and Ryan, livening up the entire picture by adding the comedic quality that simply wasn’t on the page. Key is hilarious, running circles around the stars and the entire film in general, and if there is any sliver of a silver lining, it’s that his performance here shows that he can carry a film on his own.

But those few moments can’t make up for the rest of this deeply uninspired, poorly shot picture, which at times feels like it was rushed to get in the can before Johnson and Wayans Jr. had to return to the set of “New Girl.” The entire effort feels slack, taking for granted the skill with which it takes to make comedy work. Just like Ryan and Justin, who learn that just because you wear the uniform doesn’t mean you know what to do when things get violently real, Greenfield would be wise to note that just because you sit behind the camera doesn’t mean you’re directing a film just by saying “action!” and “cut!” [D]